1. Field of the Invention
The present invention relates generally to the string-up of the leading portion of a continuous filament inline from a continuous forming operation onto a take-up device. More particularly, it relates to the winder string-up of the leading portion of a continuous metal filament, such as a glassy alloy strip, moving at high speed as it departs a moving quench surface in a high speed continuous casting process.
2. Description of the Prior Art
In the production of glassy alloy continuous filaments, typically an appropriate molten alloy is quenched at extreme quench rates, usually at least about 10.sup.4 .degree. C. per second by extruding the molten alloy from a pressurized reservoir through an extrusion nozzle onto a high speed rotating quench surface, as is representatively shown in U.S. Pat. No. 4,142,571 for "Continuous Casting Method for Metallic Strips" issued Mar. 6, 1978, to M. Narasimhan, which is hereby incorporated by reference thereto. Such filaments are necessarily thin, typically about 25-100 microns, because of the extreme heat transfer rate required to prevent substantial crystallization, though considerable selectivity may be exercised respecting the transverse dimension and cross-section of the filament. Thus, hereinafter in the specification and claims, the term filament is intended to include strips, both narrow and wide, as well as wire-like filaments.
It is commercially desirable to wind the filament inline with its casting process, as representatively shown in U.S. Pat. No. 3,938,583 "Apparatus for Production of Continuous Metal Filaments" issued Feb. 17, 1976, to S. Kavesh. However, initiation of winding inline with a casting process is especially difficult for at least two reasons. First, linear casting speeds are high, and string-up must be accomplished quickly and precisely; otherwise an entangled mass of filament accumulates rapidly. Second, the tension exerted on the filament during string-up must be maintained within limits. Tension must be sufficient to substantially dampen disrupting oscillations of the filament (excessive "flutter") but not so much as to disrupt the quenching operation.
A typical winder string-up apparatus, with counter-rotating brush rollers traveling along a raised track, is shown in U.S. Pat. No. 4,239,187 "Winder String-Up Method and Apparatus" issued Dec. 16, 1980 to B. Boggs, et al.
The device disclosed in Boggs, et al., however, lacks sufficient maneuverability. If the string-up apparatus should miss capturing the leading edge of the advancing filament, the filament may become entangled in the associated winder apparatus ruining the cast material and causing the material to be scrapped. Also, improved means for increasing the filament contact are around the winding wheel is needed to provide a more versatile cut and grip operation, and a modulated rate of filament transfer is needed to minimize breakage of the filament. Thus, there is continued need for a more maneuverable and efficient string-up apparatus which provides an increased filament contact arc and modulated rate of movement.